C88.90
BillableMalignant immunoproliferative disease, unspecified not having achieved remission
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C88.90 an HCC code?
Yes. C88.90 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for C88.90
For C88.90 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C88.90 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C88.90 is the ICD-10-CM diagnosis code for malignant immunoproliferative disease, unspecified not having achieved remission. A cancer of immune cells of an unspecified type that has not responded to treatment or is still active. C88.90 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).
Under the CMS-HCC V28 risk adjustment model, C88.90 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C88.90 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation. Because C88.90 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C88.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation
- •The fifth character '0' indicates the disease has not achieved remission; document treatment response status
Clinical Significance
Malignant immunoproliferative disease, unspecified, not having achieved remission is the least specific code in the immunoproliferative disease category, used when neither the type of immunoproliferative disease nor the site can be determined from available documentation. This code should prompt a query to the provider for additional diagnostic information. Active disease that has not achieved remission indicates ongoing malignant process.
Documentation Requirements
- ✓Even for unspecified codes, documentation should include available clinical findings, laboratory results, and any pathology that has been obtained.
- ✓The reason the specific type cannot be determined should be evident in the record.
- ✓Treatment plan, response assessment, and active disease status must be documented.
- ✓Provider queries for additional specificity should be documented.